floodgate (n.)

• avenue
• blowhole
• channel
• chute
• door
• egress
• escape
• estuary
• exhaust
• exit
• flume
• gate
• lock
• loophole
• opening
• out
• outcome
• outfall
• outgo
• outlet
• penstock
• pore
• port
• sluice
• spiracle
• spout
• tap
• vent
• venthole
• vomitory
• weir